Hardening cementitious materials.



I UUI UUIVII'UOI l IUHO,

COATING R PLASTIC.

UNITED STATES AARON C. HORN, O

F NEW YORK, N. Y.

EARDENING CEMENTITIOUS MATERIALS.

1,114,140. No Drawing.

Specification of Letters Patent.

Patented Oct. 20, 1914.

Application filed October 9, 1912. Serial No. 724,742.

To all whom it ma concern:

Be it known t at I, AARON C. HORN, a citizen of the United States, and a resident of New York, in the county of New York and State of New York, have invented certain new and useful Improvements in Hardening Cementitious Materials, of which the following is a specification.

This invention relates to a 239M, denin and solidifying cemen itious matar I la nioiegfie'rally of the nature of Portfirwid a ngrait and concrete, and to the prodo d process, namely a hardened structural mass preferably colored certain characteristic colors or shades; and in some forms becoming a duplex or multiplex cementitious structure by the cementing together of two or more layers or strata of different compositions and relative hardness; all as more fully hereinafter described and as claimed.

The surface of ordinarv concrete, even when laid with the greatest precautions, nearly always exhibits the undesirable ropriety of dusting on slight attrition. his is unimportant, in the case of walls and vertical structures, generally speaking, but 'is of serious consequence in the case of floors, sidewalks and the like where attrition quickly causes deterioration. been made to harden the surface of concrete which has to be subjected to such attrition, but no cheap and easily applied material of a a thoroughly efl'ective nature has been heretofore proposed. Silicate of soda ha s been tried as a., sn..% .yvash, but 'does not have .the desired hardening qualities, especially as applied to a floated surface of fine grain and but slightly porous. The usg of the @usilicates a lso has been recomrhend d, ese' are probabl'y of considerable utility except for the rather high cost of the materials. Powdered meta lp es eci a ll irmas been fi's'd'biithis certaifi disadvantages among which is the tendency to gradually discolor the concrete by progressive changes on protraoted exposure.

By my invention cheap and easily ob-- tainable materials may be used which also enable the concrete to be suitably colored in certain shades without the addition of inert color-in material such as ordinary Many attempts have oxid of iron, 3 I r and the other customary pigm i for coloring cement, but which if anything have an undesirable action or eflect on the strength. Under my invention, is afforded the opportunity to obtam certain permanent colors in concrete without impairing the strength and in fact with increase of the hardness of the result- 111 surface.

31y inyention ii iyolygs the cement oro'fi'c'rete of a quantity of a valencychanging material of a potentially-bonding character, more specificall an oxid capable oi ehangeoiewalence un er the condltions imposed in concrete structural work.

The ordinary oxids of iron of the F e 0 type are incapa e o r or change ofvalency and cannot be used to good advantage in the present process except as fillers or inert material, in which case there is no gain in such use, and often a detrimental action. Q,

On the other h n xids of the Fe 0, type have certain ver" concrete mixtures under conditions as will be hereinafter set forth, and may bop l1? W while at the same me o g o e mass a desirable shade of color. Thus while oxids of the hematite type usually tend to ecrease e ar ess 'o'f'irconcrete surface thee v r p parently a new pr duct, with particles of magnetite or its products of reaction actually bonded and combined therewith. *In order to secure magnetite material reactive to the most serviceable degree I pre- 95 tocaIcinethe raw ore at a low temperature',re a 1 e y 'spea rig, and to then r' d uenc a ema- E: i fi e in: Preferably alsoI e ea o magnetite in water after c l tion in order to render it more easily ground and improve its reactivity. Preferably the magnetite material should be reduced to the fineness of Portland cement or thereabout to secure the best results. The ordinary magnetite afl'ords a black or nearl black colored concrete and some of the cal cined material gives a maroon color which is very pleasing 1n appearance. In mixing the active magnetite thus obtained or as de- 0 material, instead of weakfiing th fcement tite material, 24 p rived in any other suitable manner, I preferably mix the dry materials to thoroughly incorporate and then add water to make a plastic mass. This is then formed into shape and allowed to set. The active magnetite may also be mixed with the dry cement and subsequently incorporated with the aggregate, if used. ater-proofing materials may be added as required, preferably using, however nium ste. ate material nd thelike. Mamount of calcium chlorid in tale wager usBed for gaging 1e co e is esira le. chlorid may be mixed with the ma 31% various propmmmst t e set more or less, and accelerate the reaction to some extent under certain circumstances. It should here be stated that although the magnetite material is suiiiciently active if properly prepared, to not require such accelerating material, yet if over calcined or otherwise improperly treated it may require greater or less amounts of accelerating material of the nature of barium ghlorid.

When mixed in accor ance wit 1 the foregoing; only 10% of the magnetite material is su cient to harden the cement remarkably, and also to afford a desirable shade or shades of color. Ten per cent. of ordinary iron oxid coloring material would weaken the cement but this amount of the magnetite and increasing the dusting as would perhaps be expected, has quite the contrary and unexpected action of hardening the product to greatly reduce or eliminate dusting.

A special surface of great hardness may be made by mixing equal parts of Portland cement and magnetite active material rendering plastic with water andTr'oweling on a concrete surface or foundation to yield a dustless or practically dustless finishing coat. Another formula suitable in this connection is made by mixing 43 parts of Port-,, land cement 30 parts finely round ma t of crusfied ma etite and 3 parts of finely ground ferrous sulfate. Bififietive black 0 may a o be adde 1 esire e Ql1 $;1 1fate is in itself a hardening material to some extent but the amount which may be used is perhaps usually regu-\ lated by the effect on the setting time of the cement. The foregoing proportions may be varied more or less according to the structure which is to be treated and its use.

I believe the peculiar action of the active magnetite material to be due to its capacity to change in valency when in contact with the wet concrete materials, thereby producing a bond between the iron and lime or other materials present causin the hardening observed. As to the precise nature of vance any details but content myself with calling attention to the observed changes.

In the foregoing formulas I have mentioned illustratively several bodies of equivalent character, etc., which may be used under the present invention, but it is to be noted that by such illustrative disclosure I no not limit myself to the exact formulas or combinations mentioned, but may use other materials, giving like results or functionally similar and hence may invoke the doctrine of equivalency in so far as same may be thus applicable. For example, fggrous sulfate or a mixture of a ferrous and a ferents of the concrete mixture. Man anese salts may similarly be used in some cases.

A further feature of my invention is that which involves the use of carbid of iron or similar carbid material in or an or 0 er hydraulic cement.

s a pro no no obtainable in native conditions so far as I am advised, but can be derived commercially from high carbon steel. This compound may be added in proportion varying from about 2% to 15% or so, to cement mortar and such additions enable the production of a surface of great density, but essentially or substantially free from any mgreasedmbrasiveu ualities due,to the presenceuofihg carbid. other words, the V carbid of iron lends hardness to the cement concrete without increasing its undesirable erosive qualities.

hasa ebii aiionnf r 1 W provi e a composi 1011 of especia y ood hardenin ro erties more particularl when a considerable proportion of sand is employed in the concrete. A mixture of equal parts of magnetite and iron carbid serves for ordinary purposes and these proportions may be varied more or less preferably using say one part of v magnetite to three parts of iron carbid in case the cement mortar contains any material quantities of clayey bodies present by accident or design; and on the other hand increasing the proportion of magnetite to three parts or so to one part of carbid in the case of mortars containing sand of moderate sharpness in considerable quantities.

What I claim is;

1. The process of making a hardened concrete which comprises incorporating with cement materials a quantity of active magnetite, ferrous sulfate and black oxid of manganese, m working up to a plastic mass vilith water and in forming into any desired s ape.

2. A new cementitious material comprising Portland cement and a mixture of magnetite, ferrous sulfate and black oxid of this reaction I am however unable to admanganese.

medm hmrthemaghfite' with suita le proportioning of the compon- .withnao 3. A new oementitious material oompris- Signed at New York city in the county of ing hydraulic cement and a mixture of mag- New York and State of New York this 30 1o netite, ferrous sulfate and black oxicl of day of September A. D. 1912.

manganese. 3 4. A new cementitious material compris- AARON HORN ing hydraulic cement and a mixture of com- Witnesses: minuted magnetite, ferrous sulfate and Enwm D. NEWMAN, black oxid of manganese. Gammon ELLIS.

Omen of this patent my be obtained for in cents each, by addresdngthe commissioner ot intents,

Washington, D. 0. 

